6 Ups & 5 Downs From Doctor Who Series 12
1. Everything (Bar The Finale) Was Set On Earth
The first series of NuWho back in 2005 suffered a similar criticism. It was all past/present/future Earth, or at least on a space station in orbit of the planet we all know so well. The second series brought new planets to stand on, and a mix of familiar and alien terra firma was established since. However, each and every story of Series 12 was set on Earth (even if we didn't realise initially) up until the penultimate episode, Ascension of the Cybermen.
There's nothing outright wrong with Earth being heavily used. At the end of the day, it's in the established canon that The Doctor does love a bit of the old human race, and an entire season was set on Earth after the Third Doctor was exiled there by the Time Lords themselves! However, the severe lack of variety showed us nothing more than uninspired writing, and budgetary constraints. If a Dalek ship could be made out of a warehouse covered in tinfoil (Victory of the Daleks), then surely more could have been done with whatever money we had in the kitty this year.
And now on to the positives...